Journal of Vascular and Endovascular Therapy

Description

Coronary artery disease is virtually ubiquitous in adults with diabetes mellitus compared with no diabetic patients and portends a worse prognosis.1 As the prevalence of diabetes mellitus increases worldwide, the challenges for the health care of these individuals are magnified. Although diabetic patients account for an increasing number of patients undergoing coronary artery revascularization, they experience worse outcomes than do no diabetic patients undergoing either coronary artery bypass graft surgery or percutaneous coronary intervention. The unique pathophysiology of atherosclerosis in patients with diabetes provides a framework for understanding their response to both medical therapy and revascularization. With this background, clinical outcomes potentially can be improved in this high-risk group. The purpose of this review is to summarize the current state of evidence comparing the effectiveness and safety of CABG and PCI in diabetic patients. Evidence is also presented on specific factors that affect the outcomes of coronary revascularization in diabetic patients, including use of drug-eluting stents, glycoprotein (Gp) IIb/IIIa receptor inhibitors, and primary PCI.

Chronic Total Occlusions

Although patients with diabetes frequently have concurrent risk factors, diabetes itself is a powerful independent risk factor for cardiovascular events. There are several pathophysiologic features of atherosclerosis in diabetic patients that contribute to their worse prognosis and unique response to coronary revascularization. Metabolic and hematologic abnormalities associated with type 2 diabetes include hyperglycemia, insulin resistance, dyslipidemia, inflammation, and thrombophilia. Platelets express more Gp IIb/IIIa receptors and are more prone to aggregation, particularly in the presence of hyperglycemia.Together these abnormalities contribute to development of hypertension, endothelial cell dysfunction, accelerated atherogenesis and, eventually, coronary thrombosis. Diabetic nephropathy, including reduced creatinine clearance and proteinuria, identifies patients with markedly decreased survival after coronary revascularization. The anatomical patterns of CAD in diabetic patients may influence their prognosis and response to revascularization. Autopsy and angiographic studies have demonstrated that persons with diabetes more frequently have left main coronary artery lesions, multivessel disease, and diffuse CAD. Diabetic patients have smaller luminal diameters in segments adjacent to obstructive coronary lesions and more completely occluded segments. Lower extremity peripheral arterial occlusive disease poses a unique challenge to traditional angioplasty-based endovascular therapies. The diffuse nature of lower extremity atherosclerotic disease, the presence of chronic total occlusions, poor distal runoff, and the presence of critical limb ischemia all have contributed to the disappointing results of balloon angioplasty for complex infrainguinal arterial disease. These challenges have spawned the development of a host of new technologies in an attempt to improve the safety and effectiveness of percutaneous revascularization for lower extremity peripheral arterial occlusive disease. This review summarizes the recent advances in available technologies, including novel angioplasty balloons; nitinol stents, stent grafts, and drug-eluting stents; excisional, laser, and rotational atherectomy devices; devices for crossing total occlusions; true-lumen reentry devices; thrombectomy catheters; and embolic protection devices.

Vascular

After the onset of ischemia, cardiac or skeletal muscle undergoes a continuum of molecular, cellular, and extracellular responses that determine the function and the remodeling of the ischemic tissue. Hypoxia-related pathways, immunoinflammatory balance, circulating or local vascular progenitor cells, as well as changes in hemodynamical forces within vascular wall trigger all the processes regulating vascular homeostasis, including vasculogenesis, angiogenesis, arteriogenesis, and collateral growth, which act in concert to establish a functional vascular network in ischemic zones. In patients with ischemic diseases, most of the cellular (mainly those involving bone marrow-derived cells and local stem/ progenitor cells) and molecular mechanisms involved in the activation of vessel growth and vascular remodeling are markedly impaired by the deleterious microenvironment characterized by fibrosis, inflammation, hypoperfusion, and inhibition of endogenous angiogenic and regenerative programs. Furthermore, cardiovascular risk factors, including diabetes, hypercholesterolemia, hypertension, diabetes, and aging, constitute a deleterious macroenvironment that participates to the abrogation of postischemic revascularization and tissue regeneration observed in these patient populations. Thus stimulation of vessel growth and/or remodeling has emerged as a new therapeutic option in patients with ischemic diseases. Many strategies of therapeutic revascularization, based on the administration of growth factors or stem/progenitor cells from diverse sources, have been proposed and are currently tested in patients with peripheral arterial disease or cardiac diseases. This review provides an overview from our current knowledge regarding molecular and cellular mechanisms involved in postischemic revascularization, as well as advances in the clinical application of such strategies of therapeutic revascularization